JPH05224460A - Nonmagnetic one-component toner - Google Patents

Abstract

PURPOSE:To obtain a toner which does not influenced by long-term storage or environmental changes, maintains the initial characteristics even for continuous use, and does not cause the aggregation of the toner, changes in electrification property, or toner filming. CONSTITUTION:This nonmagnetic one-component toner is used for picture forming method in which a thin layer toner is supplied to a latent image carrier to develop a latent image. This toner shows >=40muC/g absolute value of the blow-off charge by triboelectrification with the carrier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component toner used in an image forming method by a non-magnetic one-component developing system used in the field of electrophotography and the like.

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in US Pat. No. 2,297,691.
Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-43
As disclosed in various publications such as JP-A-24748, generally, an electrostatic latent electric latent image is formed on a photoreceptor containing a photoconductive substance by various means, and then the latent image is developed as a powder image with a toner. If necessary, the powder image is transferred to paper and then fixed by heating, pressurizing, solvent vapor or the like.

Further, in recent years, an electrostatic latent image of an original is formed by exposing it to light that has been spectrally dispersed, and this is developed with color toners of respective colors to obtain colored copy images, or copy images of respective colors are superposed. A color copying method for obtaining a full-color copied image has been put into practical use, and yellow, magenta, cyan, and other color toners in which dyes and / or pigments of respective colors are dispersed in a binder resin are manufactured as color toners used for the method. ing.

As a toner developing method, a non-magnetic one-component developing method has recently been adopted in order to downsize the apparatus, simplify maintenance, and cope with colorization.
As the non-magnetic one-component developing method, a contact developing method such as a touch-down method and a flying developing method such as a projection method are known. In any case, non-magnetic toner is coated on a developing sleeve by a coating member such as an elastic blade. The point is to apply a thin layer uniformly.

[0005]

However, in the non-magnetic one-component developing method, generally, the triboelectric chargeability imparted to the toner is low, so that the toner is not likely to be conveyed or uneven on the developing sleeve, and the toner is not uniform. It is difficult to apply a thin layer. For this reason, toner scattering may occur to contaminate the inside of the copying apparatus, or cause image quality defects such as uneven image density and increased fog on the copy. This is because the method of imparting the charging property to the toner in the non-magnetic one-component developing method is the contact between the toner and the developing sleeve or the elastic blade. It is estimated that both the contact opportunity and contact area of Therefore, in the non-magnetic one-component toner, it is necessary to obtain a high charge amount quickly and stably even with a small contact opportunity and contact area.

Further, in the case of color toner, there is a variation in toner charge due to the colorant, and therefore, it has been particularly required to improve the charging property. As described above, in the color toner conventionally used for the non-magnetic one-component developing method, it is required that the color toner has good hue and transparency as a color toner and has high triboelectrification ability and durability. I was not satisfied with.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has been made to solve the problems. The purpose of the present invention is to provide the following performances, resulting in excellent stability and durability over time. An object of the present invention is to provide a non-magnetic one-component toner used in an image forming method using a magnetic one-component developing method. The charge rises quickly. Highly charged and uniform. Charging is stable even under high temperature and high humidity environment. There is little change in image quality even during continuous use.

[0008]

Means for Solving the Problems As a result of intensive investigations by the present inventors in order to achieve such an object, the above object was found to be achieved by using a toner having a specific charge amount in an image forming method by a non-magnetic one-component developing system. The inventors have found that they can be satisfied and arrived at the present invention. That is, the gist of the present invention is a non-magnetic one-component toner used in an image forming method of developing a latent image by supplying a thinned toner to a latent image carrier, and a friction of the toner with a carrier. The non-magnetic one-component toner is characterized in that the amount of blow-off charge due to charging is 40 μC / g or more in absolute value.

The present invention will be described in detail below. The non-magnetic toner used in the present invention includes a binder resin, a colorant,
A charge control agent or the like is used as a component. Among these, various known resins can be used as the binder resin. For example, polystyrene, chloropolystyrene, poly-α-
Methyl styrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene -Styrene such as methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-acrylonitrile-acrylic acid ester copolymer, etc. Resin (styrene or styrene substitution Homopolymers or copolymers containing a)
Vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin,
Ethylene-ethyl acrylate copolymer, xylene resin,
Examples thereof include polyvinyl butyral resin. Of these, styrene resins, epoxy resins and polyester resins can be advantageously used, and among them, polyester resins are particularly preferable.

The polyester resin comprises a polyhydric alcohol and a polybasic acid, and if necessary, at least one of the polyhydric alcohol and the polybasic acid contains a trifunctional or higher polyfunctional component (crosslinking component). It is obtained by polymerizing the product. In the above, examples of the dihydric alcohol used for synthesizing the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,
3-propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,4-butenediol,
Diols such as 1,5-pentanediol and 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A,
Examples thereof include bisphenol A alkylene oxide adducts such as polyoxypropyleneized bisphenol A, and the like. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as a main component monomer, and among them, an adduct having an average alkylene oxide addition number of 2 to 7 per molecule is preferable.

Examples of the trihydric or higher polyhydric alcohol involved in the crosslinking of the polyester include sorbitol and
1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol , 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and the like.

On the other hand, examples of the polybasic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid and azelaic acid. Examples thereof include acids, malonic acids, anhydrides of these acids, lower alkyl esters, alkenylsuccinic acids or alkylsuccinic acids such as n-dodecenylsuccinic acid and n-dodecylsuccinic acid, and other divalent organic acids.

Examples of the tribasic or higher polybasic acid involved in the crosslinking of the polyester include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid,
1,2,4-cyclohexanetricarboxylic acid, 2,5
7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octane tetracarboxylic acid, these anhydrides, etc. can be mentioned.

These polyester resins can be synthesized by a usual method. Specifically, the reaction temperature (1
Conditions such as 70 to 250 ° C.) and reaction pressure (5 mmHg to normal pressure) are determined according to the reactivity of the monomer, and the reaction may be terminated when predetermined physical properties are obtained. When the softening point of these polyester resins is lower than 90 ° C., they easily cause blocking, resulting in poor storage stability and mechanical durability. If the softening point exceeds 150 ° C., the fixing performance will deteriorate,
In particular, color toner is not preferable because it causes difficulty in transparency and gloss. Therefore, the softening point of the resin is 90 to 15
It is preferably in the range of 0 ° C, and further 100 to 130.
More preferably, it is in the range of ° C.

Further, in general, when the acid value of the polyester resin is too high, it is difficult to obtain a stable high charge amount,
In addition, since the charging stability tends to deteriorate at high temperature and high humidity, the acid value of the present invention is 30 KOHmg /
g or less, more preferably 20 KOHmg
It is preferable to adjust it so that it is less than / g. As a method for adjusting the acid value within the above range, other than the method of controlling the addition ratio of the alcohol-based and acid-based monomers used in the resin synthesis, for example, the acid monomer component is previously converted into a lower alkyl ester by a transesterification method. Examples of the known method include, but are not limited to, a method of synthesizing a residual acid group by adding a basic component such as an amino group-containing glycol to the composition, and a method of synthesizing the residual acid group. Needless to say, can be adopted.

The acid value of the polyester resin is JIS
It is measured according to the method of K0070. However, if the resin is difficult to dissolve in the solvent, a good solvent such as dioxane may be used. Next, any suitable pigment or dye is used as the colorant contained in the non-magnetic toner according to the present invention. For example, carbon black, lamp black, iron black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine pigment, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, anthraquinone dye, Any conventionally known dyes and pigments such as monoazo and disazo dyes and pigments may be used alone or in combination. These colorants are preferably 0.5 to 2 with respect to 100 parts by weight of the binder resin.
It is used in an amount of 0 part by weight, more preferably 2 to 10 parts by weight.

As the charge control agent, all known charge control agents can be used. For example, there are nigrosine dyes, amino group-containing vinyl copolymers, quaternary ammonium salt compounds, polyamine resins, etc. for positive charging properties, and metals containing chromium, zinc, iron, cobalt, aluminum, etc. for negative charging properties. Known are metal azo dyes, salts of salicylic acid or alkylsalicylic acid with the above-mentioned metals, metal complexes and the like. The amount used is preferably 0.1 to 25 parts by weight, and more preferably 1 to 100 parts by weight of the resin.
~ 15 parts by weight is preferred. In this case, the charge control agent may be added to the resin or may be used in the form of being attached to the surface of the toner particles.

Among these charge control agents, in consideration of the charge imparting ability to the toner and the color toner adaptability (the charge control agent itself is colorless or light-colored and does not hinder the color tone of the toner), the charge control agent is used for positive chargeability. Is preferably an amino group-containing vinyl copolymer and / or a quaternary ammonium salt compound, and for negative charging, a metal salt or metal complex of salicylic acid or alkylsalicylic acid with chromium, zinc, iron, cobalt, aluminum or the like is preferable.

Of these, examples of the amino group-containing vinyl copolymer include copolymer resins of amino acrylates such as N, N-dimethylaminomethyl acrylate and N, N-diethylaminomethyl acrylate, and styrene and methyl methacrylate. Can be mentioned. Examples of the quaternary ammonium salt compound include tetraethylammonium chloride, a salt-forming compound of benzyltributylammonium chloride and naphtholsulfonic acid, and the like. For a positively chargeable toner, the above amino group-containing vinyl copolymer and the quaternary ammonium salt compound may be added alone or in combination.

As the metal salt or metal complex of salicylic acid or alkylsalicylic acid, chromium or zinc complex of 3,5-ditertiary-butylsalicylic acid is particularly preferable among various known substances. Further, in order to improve the dispersibility and compatibility in the toner, the above colorants and charge control agents may be subjected to pre-dispersion treatment, so-called masterbatch treatment, by pre-kneading with a resin.

As the other constituent components of the toner of the present invention, for example, the following substances may be added.・ Fluidity improver such as colloidal silica ・ Cleaning aid such as metal stearate ・ Release agent such as low molecular weight polypropylene

The non-magnetic toner according to the present invention can be manufactured by various manufacturing methods including conventionally known methods. The general manufacturing method includes the following examples. A resin, a charge control substance, a colorant, and additives that are added as necessary are uniformly dispersed with a Henschel mixer or the like. The dispersion is melt-kneaded with a kneader, an extruder, a roll mill or the like. After roughly kneading the kneaded product with a hammer mill, a cutter mill or the like, it is finely crushed with a jet mill, an I-type mill or the like. The finely pulverized product is classified by a dispersion classifier, a zigzag classifier, or the like. Depending on the case, silica or the like is dispersed in the classified product with a Henschel mixer or the like.

Further, as a method completely different from the above-mentioned manufacturing method, for example, there may be mentioned a manufacturing method by a suspension polymerization method. As described above, the non-magnetic toner according to the present invention has a triboelectric charge amount of 40 μC / g or more in absolute value when mixed with a carrier to form a so-called two-component developer, and more preferably 4
It is characterized by being 5 μC / g or more. That is, when a toner capable of obtaining a constant high charge amount by frictional charging with a carrier is applied to an image forming method by a non-magnetic one-component developing method, the object of the present invention is sufficiently satisfied and stability with time and durability are improved. It was found that the desired result was obtained. Further, if the charge amount is less than the above value, a good image cannot be obtained and the durability is poor.

The charge amount was measured as follows. After placing 1 g of the non-magnetic toner according to the present invention and 19 g of a carrier (ferrite carrier DFC-150, manufactured by Dowa Iron Powder) in a 30 cc glass sample bottle, a vibrating mixer mill (Type MM, manufactured by Riken Mitamura).
And was stirred at a shaking strength scale of 50 for 30 minutes to prepare a developer. Then, a triboelectric charge amount was measured with a blow-off powder charge amount measuring device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) using a SUS316 400-mesh wire net.
The measurement conditions are as follows. Blow gas: Nitrogen Blow pressure: 1 kg / cm ² Blow time: 20 seconds Amount of developer used: 0.2 g

The toner of the present invention is useful for image formation by a non-magnetic one-component developing system in electrophotography. The image forming method of the present invention will be described below. The image forming method of the present invention is based on a non-magnetic one-component developing method in electrophotography, in which a thinned toner is supplied to a latent image carrier to develop the latent image. Incidentally, the thinning of the toner is usually provided with a toner conveying member, a toner layer thickness regulating member and a toner replenishing auxiliary member, and the replenishing auxiliary member, the toner conveying member and the toner layer thickness regulating member and the toner conveying member are respectively provided. This is done using the abutting device.

The image forming method using the toner of the present invention will be described in more detail with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a developing device using a non-magnetic one-component toner that can be used for carrying out such an image forming method. In the drawing, the toner 6 of the present invention contained in the toner hopper 7 is forced to the sponge roller (toner replenishment auxiliary member) 4 by the stirring blade 5, and the toner is supplied to the sponge roller 4. Then, the toner taken into the sponge roller 4 is carried to the toner conveying member 2 by the rotation of the sponge roller 4 in the direction of the arrow, and is rubbed and electrostatically or physically adsorbed, and the toner conveying member 2 is It strongly rotates in the direction of the arrow, and a uniform thin toner layer is formed by a steel elastic blade (toner layer thickness regulating member) 3 and is triboelectrically charged. After that, the toner is conveyed to the surface of the electrostatic latent image carrier 1 which is in contact with or in the vicinity of the toner conveying member 2, and the latent image is developed. The electrostatic latent image is obtained, for example, by exposing the organic photoconductor to a DC charge of 500 V and then exposing it.

In the image forming method in the non-magnetic one-component developing method for electrophotography as described above, fluctuations in the charging property of the toner greatly affect the forming property of the thin layer of the toner, but the toner according to the present invention is stable. Since it exhibits the triboelectrification property and is excellent in environmental stability, it is possible to control the charge amount to an appropriate value during the execution, and the method of the present invention can provide a high-quality image for a long period of time.

[0028]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, in each of the Examples and Comparative Examples, simply "part" means "part by weight". Production of Polyester Resins 1 to 3 The materials having the compositions shown in Table 1 were placed in a glass 3-liter four-necked flask, a thermometer, a stainless steel stirring rod, a downflow condenser and a nitrogen introduction tube were attached, and an electric heating mantle heater was used. Under a nitrogen stream, the first half 200 ℃ normal pressure, the second half 2
The reaction proceeded while stirring at 20 ° C. under reduced pressure. The reaction state was traced while measuring the acid value, and the reaction was stopped when the acid value reached a predetermined value, and then cooled to room temperature to obtain each polyester resin.

[0029]

[Table 1]

In Table 1, alcohol and acid components are represented by abbreviations and symbols, but they represent the following raw material names. Diol A: Polyoxypropylene (2.2)
-2,2-bis (4-hydroxyphenyl) propane diol B: polyoxyethylene (2.2)-
2,2-bis (4-hydroxyphenyl) propane EG: ethylene glycol TPA: terephthalic acid IDSA: isododecenyl succinic acid TMAA: trimellitic anhydride Table 2 shows the physical property values of the above polyester resins.

[0031]

[Table 2]

A flow tester (CFT-500 type, manufactured by Shimadzu Corporation) was used to measure the softening point of the resin. Comparative Example Production of Polyester Resin 4 Polyester N was selected from those listed in Table 1 above.
o. Using the material having the same composition as that of No. 3, the reaction was carried out in exactly the same manner as in the method for producing the polyester resin. The reaction was allowed to proceed while measuring the acid value, the reaction was stopped when the acid value reached a predetermined value, and then the mixture was cooled to room temperature to obtain each polyester resin. Table 3 shows the physical property values of these polyester resins.

[0033]

[Table 3]

Examples 1 to 7 and Comparative Examples 1 to 2 Table 4 shows a list of toner compositions of Examples 1 to 7 and Comparative Examples 1 and 2.

[0035]

[Table 4]

The method for producing the toner was as follows. Melt and knead each toner material with a kneader,
After cooling, it was coarsely pulverized using a hammer mill and then finely pulverized by an air jet type fine pulverizer. The obtained fine powder was classified to select a particle size of 5 to 20 μm to obtain a toner. The volume average particle diameters measured by a Coulter counter were all within the range of 10 ± 0.5 μm.
0.5 part of fine particle silica (Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was externally added to 100 parts of these toners using a Henschel mixer.

The blow-off charge amount of these toners is measured by the method described above. In addition, these toners were evaluated by an actual copying test using the developing device shown in FIG. In this case, in order to confirm the durability of the toner, a running test of about 20,000 sheets was performed, and the fluctuation of the image quality was mainly visually observed. In addition, in order to see the effect of the measurement environment, the actual photograph is in a normal environment with a temperature of 25 ° C. and a relative humidity of 55 ± 5%,
And an exactly similar experiment was conducted in a high temperature and high humidity environment of a temperature of 40 ° C. and a relative humidity of 85% ± 5%.

The evaluation results are summarized in Table 5. According to this, the image forming method using the non-magnetic one-component toner of the present invention can obtain a high-quality and stable image not only under the normal environment but also under the high temperature and high humidity environment, and the durability as a toner. Also excellent in sex. On the other hand, according to the comparative example, the poor image quality resulting from the low charge amount and the remarkable decrease in durability under high temperature and high humidity environment are remarkable.

[0039]

[Table 5]

[0040]

The effects obtained by the present invention are as follows. The non-magnetic one-component toner of the present invention (1) provides a high quality copy that is not affected by environmental changes such as aging and high temperature and high humidity. (2) Even after continuous use for a long period of time, the initial characteristics are maintained, toner aggregation and chargeability change do not occur, and toner filming does not occur. (3) Excellent transparency, fastness, and good hue
A color toner having a color saturation is obtained, which is applicable to color electrophotography. As described above, according to the present invention, a stable and high-quality image can be easily obtained, so that the present invention is industrially very useful.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of a developing device useful for carrying out the method of the present invention using the toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrostatic latent image carrier, 2 ... Toner conveying member 3 ... Elastic blade (toner layer thickness regulating member) 4 ... Sponge roller (toner auxiliary replenishing member) 5 ... Stirring blade, 6-toner 7-toner hopper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Oda Inventor Hirofumi Oda 370 Enzo, Chigasaki City, Kanagawa Mitsubishi Kasei Co., Ltd. Chigasaki Plant

Claims (4)

[Claims] 1. A non-magnetic one-component toner used in an image forming method for developing a latent image by supplying a thinned toner to a latent image carrier, the toner being obtained by triboelectrification with a carrier. Absolute value of blow-off charge is 40μC /
A non-magnetic one-component toner characterized by having g or more. 2. The toner according to claim 1, wherein the toner contains a polyester resin having a softening point of 90 to 150 ° C. and an acid value of 30 KOHmg / g or less as a constituent component. Magnetic one-component toner. 3. The non-magnetic one-component toner according to claim 1, wherein the toner contains an amino group-containing vinyl copolymer and / or a quaternary ammonium salt compound as its constituent components. .. 4. The non-magnetic one-component toner according to claim 1, wherein the toner contains a metal salt or metal complex of salicylic acid or alkylsalicylic acid as its constituent component.